I am modelling a solid oxide fuel cell with SOFC module of FLUENT. I have some problem to model the activation overpotential, especially i0.

As a fact increasing the operating temperature should result in better performance i.e. higher voltage. However this effect in not captured very well. It seems the problem lies in i0 modelling which is sort of vague to me.

Can any body who is experienced in FLUENT SOFC module help me on this please.